Change eslint rule arrow-parens to always

Author: tshemsedinov

.eslintrc.json

@@ -211,7 +211,7 @@
  ],
  "arrow-parens": [
  "error",
- "as-needed"
+ "always"
  ],
  "arrow-body-style": [
  "error",

JavaScript/2-imperative-good.js

@@ -10,7 +10,7 @@
 
 const fs = require('fs');
 
-const loadFile = fileName => {
+const loadFile = (fileName) => {
  let data = null;
  try {
  data = fs.readFileSync(fileName, 'utf8');
@@ -20,7 +20,7 @@ const loadFile = fileName => {
  return data;
 };
 
-const parseFile = data => {
+const parseFile = (data) => {
  const lines = data.split('\n');
  lines.shift();
  const cities = [];
@@ -38,15 +38,15 @@ const parseFile = data => {
  return cities;
 };
 
-const calculateDensityColumn = cities => {
+const calculateDensityColumn = (cities) => {
  cities.sort((city1, city2) => city2.density - city1.density);
  const maxDensity = cities[0].density;
  for (const city of cities) {
  city.relative = Math.round(city.density * 100 / maxDensity);
  }
 };
 
-const showTable = cities => {
+const showTable = (cities) => {
  for (const city of cities) {
  const line = (
  city.name.padEnd(18) +

JavaScript/3-functional-bad.js

@@ -20,18 +20,18 @@ const width = [18, 10, 8, 8, 18, 6];
 
 let maxDensity = 0;
 
-const format = file => (
+const format = (file) => (
  fs.readFileSync(file, 'utf8').split('\n')
  .filter((s, i) => i && s)
- .map(line => line.split(',').map((cell, i, arr) => (
+ .map((line) => line.split(',').map((cell, i, arr) => (
  (i < 1 || i > 3) || (cell = parseInt(cell), arr[i] = cell),
  (i - 3) || (maxDensity = maxDensity > cell ? maxDensity : cell), cell
  )))
- .map(row => (
+ .map((row) => (
  row.push(Math.round(row[3] * 100 / maxDensity).toString()), row
  ))
  .sort((r1, r2) => (r2[5] - r1[5]))
- .map(row => (
+ .map((row) => (
  row.map((cell, i) => padding[i](cell + '', width[i])).join('')
  ))
  .join('\n')

JavaScript/4-functional-good.js

@@ -12,27 +12,27 @@
 const fs = require('fs');
 
 const proportion = (max, val) => Math.round(val * 100 / max);
-const compose = (...funcs) => x => funcs.reduce((x, fn) => fn(x), x);
+const compose = (...funcs) => (x) => funcs.reduce((x, fn) => fn(x), x);
 
 const cellPad = (i, s, width) => (i ? s.padStart(width) : s.padEnd(width));
-const cellWidth = i => [18, 10, 8, 8, 18, 6][i];
+const cellWidth = (i) => [18, 10, 8, 8, 18, 6][i];
 
 const renderCell = (cell, i) => cellPad(i, cell + '', cellWidth(i));
-const renderRow = row => row.map(renderCell).join('');
-const renderTable = table => table.map(renderRow).join('\n');
+const renderRow = (row) => row.map(renderCell).join('');
+const renderTable = (table) => table.map(renderRow).join('\n');
 
 const densityCol = () => 3;
-const sortByDensity = table => table.sort(
+const sortByDensity = (table) => table.sort(
  (row1, row2) => (row2[densityCol()] - row1[densityCol()])
 );
 const calcColumn = (table, max) => table.map(
- row => (row.push(proportion(max, row[densityCol()])), row)
+ (row) => (row.push(proportion(max, row[densityCol()])), row)
 );
-const calcProportion = table => calcColumn(table, table[0][densityCol()]);
+const calcProportion = (table) => calcColumn(table, table[0][densityCol()]);
 
-const parseTable = lines => lines.map(line => line.split(','));
-const toLines = data => data.split('\n').filter((s, i) => i && s);
-const readFile = file => fs.readFileSync(file, 'utf8');
+const parseTable = (lines) => lines.map((line) => line.split(','));
+const toLines = (data) => data.split('\n').filter((s, i) => i && s);
+const readFile = (file) => fs.readFileSync(file, 'utf8');
 const getDataset = compose(readFile, toLines, parseTable);
 
 const main = compose(getDataset, sortByDensity, calcProportion, renderTable);

JavaScript/5-functional-alternative.js

@@ -4,29 +4,29 @@ const fs = require('fs');
 
 const proportion = (max, val) => Math.round(val * 100 / max);
 
-const compose = (...funcs) => x => funcs.reduce((x, fn) => fn(x), x);
+const compose = (...funcs) => (x) => funcs.reduce((x, fn) => fn(x), x);
 
 const densityCol = 3;
 const cellWidth = [18, 10, 8, 8, 18, 6];
 
-const renderTable = table => table
- .map(row => row
+const renderTable = (table) => table
+ .map((row) => row
  .map((cell, i) => cell
  .toString()[(i ? 'padStart' : 'padEnd')](cellWidth[i]))
  .join(''))
  .join('\n');
 
-const calcProportion = table => (
+const calcProportion = (table) => (
  table.sort((row1, row2) => (row2[densityCol] - row1[densityCol])),
- table.map(row => (
+ table.map((row) => (
  row.push(proportion(table[0][densityCol], row[densityCol])), row
  ))
 );
 
-const getDataset = file => fs.readFileSync(file, 'utf8')
+const getDataset = (file) => fs.readFileSync(file, 'utf8')
  .split('\n')
  .filter((s, i) => i && s)
- .map(line => line.split(','));
+ .map((line) => line.split(','));
 
 const main = compose(getDataset, calcProportion, renderTable);
 

JavaScript/6-functional-pure.js

@@ -3,32 +3,32 @@
 const fs = require('fs');
 
 /* fp */
-const pipe = (...fns) => x => fns.reduce((v, f) => f(v), x);
-const curry = fn => (...args) => fn.bind(null, ...args);
+const pipe = (...fns) => (x) => fns.reduce((v, f) => f(v), x);
+const curry = (fn) => (...args) => fn.bind(null, ...args);
 const map = curry((fn, arr) => arr.map(fn));
 const join = curry((str, arr) => arr.join(str));
 const split = curry((splitOn, str) => str.split(splitOn));
 const sort = curry((compareFn, arr) => arr.sort(compareFn));
 const filter = curry((filterFn, arr) => arr.filter(filterFn));
 
 /* utility */
-const first = arr => arr[0];
-const skipFirst = arr => arr.slice(1);
-const hasValue = val => !!val;
-const toStr = val => val.toString();
+const first = (arr) => arr[0];
+const skipFirst = (arr) => arr.slice(1);
+const hasValue = (val) => !!val;
+const toStr = (val) => val.toString();
 const appendCell = (row, value) => row.concat(value);
 const cellPad = (index, str, width) => (
  index ? str.padStart(width) : str.padEnd(width)
 );
-const cellWidth = index => [18, 10, 8, 8, 18, 6][index];
+const cellWidth = (index) => [18, 10, 8, 8, 18, 6][index];
 
 const renderCell = (cell, index) => (
  cellPad(index, toStr(cell), cellWidth(index))
 );
 const renderRow = pipe(map(renderCell), join(''));
 const renderTable = pipe(map(renderRow), join('\n'));
 
-const getDensityCell = row => parseInt(row[3], 10);
+const getDensityCell = (row) => parseInt(row[3], 10);
 const proportion = (max, val) => Math.round(parseInt(val, 10) * 100 / max);
 const sortRowsByDensity = sort(
  (row1, row2) => getDensityCell(row2) - getDensityCell(row1)
@@ -40,16 +40,16 @@ const calcMaxDensity = pipe(
  getDensityCell
 );
 
-const calcRowsProportionToMax = rows => max => rows.map(pipe(
+const calcRowsProportionToMax = (rows) => (max) => rows.map(pipe(
  getDensityCell,
- densityCell => proportion(max, densityCell)
+ (densityCell) => proportion(max, densityCell)
 ));
 
-const appendProportionCell = rows => proportions => rows.map(
+const appendProportionCell = (rows) => (proportions) => rows.map(
  (row, index) => appendCell(row, proportions[index])
 );
 
-const appendTableProportionCol = rows => pipe(
+const appendTableProportionCol = (rows) => pipe(
  calcMaxDensity,
  calcRowsProportionToMax(rows),
  appendProportionCell(rows)
@@ -63,7 +63,7 @@ const toLines = pipe(
  filter(hasValue)
 );
 
-const readFile = file => fs.readFileSync(file, 'utf8');
+const readFile = (file) => fs.readFileSync(file, 'utf8');
 
 const getDataset = pipe(
  readFile,

JavaScript/7-mixed.js

@@ -2,13 +2,13 @@
 
 const fs = require('fs');
 
-const compose = (...funcs) => x => funcs.reduce((x, fn) => fn(x), x);
+const compose = (...funcs) => (x) => funcs.reduce((x, fn) => fn(x), x);
 
 const DENSITY_COL = 3;
 
-const renderTable = table => {
+const renderTable = (table) => {
  const cellWidth = [18, 10, 8, 8, 18, 6];
- return table.map(row => (
+ return table.map((row) => (
  row.map((cell, i) => {
  const width = cellWidth[i];
  return i ? cell.toString().padStart(width) : cell.padEnd(width);
@@ -18,20 +18,20 @@ const renderTable = table => {
 
 const proportion = (max, val) => Math.round(val * 100 / max);
 
-const calcProportion = table => {
+const calcProportion = (table) => {
  table.sort((row1, row2) => row2[DENSITY_COL] - row1[DENSITY_COL]);
  const maxDensity = table[0][DENSITY_COL];
- table.forEach(row => {
+ table.forEach((row) => {
  row.push(proportion(maxDensity, row[DENSITY_COL]));
  });
  return table;
 };
 
-const getDataset = file => {
+const getDataset = (file) => {
  const lines = fs.readFileSync(file, 'utf8').split('\n');
  lines.shift();
  lines.pop();
- return lines.map(line => line.split(','));
+ return lines.map((line) => line.split(','));
 };
 
 const main = compose(getDataset, calcProportion, renderTable);